HEIC to JPG Converter

Why HEIC is the format that will not open

HEIC is not one thing: HEIF (High Efficiency Image File Format, ISO/IEC 23008-12) is the container, and HEIC is the flavor of it that holds video-coded frames - specifically HEVC. iPhones have saved photos this way since iOS 11 because the same picture takes roughly half the bytes of a JPEG at the same visual quality, which on a phone with a small disk is the difference between two thousand photos and four thousand.

The reason it will not open has nothing to do with the file and everything to do with the decoder. HEVC is patented, licensed per device and usually implemented in the operating system rather than in the browser, so Safari 17 and later - which can hand the job to the system - opens HEIC happily, while Chrome, Edge and Firefox do not decode it on any operating system. It is not a bug in your file. It is, however, something a page can work around, which is the next paragraph.

So this page decides per file: it looks at the first bytes to see what the file really is (a HEIC renamed to `.jpg` is common, and the name is not evidence), asks the browser to decode it, and when the browser refuses the format it loads its own decoder - a self-contained HEIC decoder, 1.4 MB raw and about 440 KB over the wire, served from this origin. That download happens once per visit, only for a visitor who actually brought a HEIC, and never on the first screen: someone converting JPEGs pays nothing for it.

The other half of the confusion is AVIF. It is also a HEIF container, but the picture inside is coded with AV1, which browsers do implement, so AVIF needs no help at all. HEIC needs the decoder described above, and once it is there both convert the same way - the only difference is which decoder did the work.

What a format conversion changes, and what it costs

Converting means decoding the file into pixels and encoding those pixels again. The pixels are the same size before and after - this page never scales anything, because that is a different job (the image resizer does it) - so what changes is how the picture is stored and how much is thrown away in the process.

JPEG is lossy: it splits the picture into blocks and discards detail the eye is unlikely to miss, which is why a photograph can drop to a tenth of its size and still look right. PNG is lossless: every pixel is kept exactly, stored with deflate compression, which is superb for screenshots and flat color and terrible for photographs. WebP does both - the browser writes the lossy kind at the quality you choose - and typically lands a quarter to a third under JPEG at the same visual quality.

Two things survive and one does not. Pixel dimensions survive. Transparency survives whenever the target can hold it, and when it cannot (JPEG) the see-through pixels are put on a background color you pick. What does not survive is the metadata: GPS coordinates, camera model, the date the photo was taken and the ICC color profile all live beside the pixels rather than in them, and re-encoding through a canvas drops them. On a photo about to be published that is usually the point; on an archive it is worth knowing before you convert.

The one exception is the Exif orientation tag, and it is handled by applying it rather than keeping it: the pixels are turned to make the picture upright on the way in, so a photo taken in portrait stays upright once the tag is gone. Without that step, every phone photo converted anywhere would come out sideways.

AVIF: the HEIF that works

At first glance AVIF is the same problem as HEIC: another HEIF container, another modern codec, another photo format your software may not open. The difference decides everything - AVIF holds a picture coded with AV1, which browsers do implement, so it converts here perfectly well. Two formats that look identical on the outside and behave completely differently, which is exactly what this page should say out loud.

The same byte-level honesty applies to names. A HEIC renamed to `.jpg` is common, and the page reads the file itself, byte by byte, to decide what it really is rather than trusting the extension - so an imposter converts happily, and a real HEIC is handed to that decoder rather than turned away.

Files already in the target format, and batches of twenty

An iPhone folder is usually a mix of HEIC and JPEG, and re-encoding the JPEGs serves no one: every re-encode loses a little more. The matching setting on the form hands already-matching files back byte for byte, so only the files that need converting are touched.

Batches are twenty a run, with no queue and no account, because the work happens in your browser and memory is the only scheduler. Twenty 12-megapixel photos is comfortable; two hundred is not - so a long camera roll is two visits rather than one fight with a download manager.